"Baby blues" affect 50% or more of women after they give birth. Postpartum depression is also fairly common. Postpartum psychosis - when a new mother experiences rapidly shifting moods, confusion, delusions, erratic behavior, hallucinations and, too often, a belief that she has to harm herself or the child, is estimated to occur in 1 or 2 births per thousand .
But think about that. In the US there are about 10,000 births per day. That's 10-20 women who may develop an illness that can lead to suicide or a child's death every day.
Why does this happen?
As it turns out, a major study found that "among patients who developed postpartum psychosis after childbirth, 72%–80% had bipolar disorder or schizoaffective disorder and 12% had schizophrenia." In addition, giving birth can be the trigger that changes a prior depression diagnosis to one of bipolar.
Inpatient treatment is considered essential. Metabolic causes should be ruled out. Conventional treatment then begins with common bipolar drugs: antipsychotics, mood stabilizers and anti-anxiety drugs that are sedating, generally benzodiazepines. ECT has also been shown to be effective.
For women at risk for developing postpartum psychosis (i.e., those who have had it in the past or already have bipolar, schizophrenia or schizoaffective disorder), the careful doctor may prescribe a mood stabilizer (especially lithium) during the pregnancy or immediately after the birth.
Spinelli, M.G. "Postpartum Psychosis: Detection of Risk and Management." Am J Psychiatry. 166. (2009): 405-408. Web. 31 Aug. 2012. <http://ajp.psychiatryonline.org/article.aspx?articleid=100698>.
"Postpartum Psychiatric Disorders." MGH Center for Women's Health. Massachusetts General Hospital, n.d. Web. 31 Aug 2012. <http://www.womensmentalhealth.org/specialty-clinics/postpartum-psychiatric-disorders/>.